Toshiba T2N - Manual (Page 199)

3. User Data
186 PROSEC T2N
There is a method called ‘digit designation’ which is a special
designation method for register data. ‘Digit designation’ treats 1 digit (4
bits) of a hexadecimal number as a data unit. It is a method of
designation in which a number of digits from the designated devices (bit
positions) are made the subject of data operation. Digit designation can
be used by the transfer (FUN18) and data echange (FUN22) instructions.
In practice, in the case of the following Example, 2 digits from X0008 (that is
to say, the upper 8 bits of XW000) become the subject of data operation.
Example)
There are 5 types of digit designation - Q0, Q1, ..., Q4 which have the
following significations
Q0 ... makes the designated device 1 bit the subject of data operation
Q1 ... makes 1 digit (4 bits) with the designated device as the lead the
subject of data operation
Q2 ... makes 2 digits (8 bits) with the designated device as the lead the
subject of data operation
Q3 ... makes 3 digits (12 bits) with the designated device as the lead the
subject of data operation
Q4 ... makes 4 digits (16 bits) with the designated device as the lead the
subject of data operation
Q5 to Q8 cannot be used by the T2N.
In digit designation, when the area designated covers multiple registers,
as shown below, the area is designated from the smaller address to the
greater address.
Example)
3.5
Digit Designation
NOTE
Q4
R030C
F B 0
RW030 RW031
The 16 bits R030C to R031B (R030C is the lowest
position bit as a numerical value)
FC 0
Digit designation (in this case 2-digit designation)
Digit designation leading device
F C B 8 7 4 3 0
2nd digit 1st digit
X008
designates the hatched line area